CVE-2018-21090 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with software through 2017-11-03 (S.LSI modem chipsets). The Exynos modem chipset has a baseband buffer overflow. The Samsung ID is SVE-2017-10745 (January 2018).
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Analysis
by VulDB Data Team • 10/09/2020
The vulnerability identified as CVE-2018-21090 represents a critical buffer overflow flaw within the Exynos modem chipset used in various Samsung mobile devices. This issue affects software versions through November 3, 2017, and was subsequently documented under Samsung's internal tracking system as SVE-2017-10745. The vulnerability resides in the baseband processor component of the modem chipsets, which handles cellular communication protocols and network connectivity functions. The baseband processor serves as the primary interface between the device's operating system and the cellular network, making it a prime target for attackers seeking to compromise mobile device security. This particular flaw manifests as a buffer overflow condition that occurs during the processing of specific network messages or communication protocols received through the cellular connection.
The technical implementation of this buffer overflow vulnerability stems from inadequate bounds checking within the modem's baseband firmware. When the Exynos modem receives certain malformed or specially crafted network packets, the processing routine fails to validate the size of incoming data before copying it into fixed-size memory buffers. This lack of proper input validation allows an attacker to overwrite adjacent memory locations, potentially leading to arbitrary code execution within the modem's processing environment. The vulnerability is particularly concerning because the modem operates at a low level within the device architecture, often with elevated privileges and direct access to critical system resources. This buffer overflow condition can be triggered through various network-based attack vectors, including malicious SMS messages, specially crafted network signals, or compromised cellular network infrastructure that the device encounters during normal operation.
The operational impact of this vulnerability extends beyond simple device compromise, as it represents a significant threat to mobile device security and user privacy. Attackers who successfully exploit this buffer overflow could potentially gain unauthorized access to sensitive device functions, including the ability to intercept communications, access stored data, modify device behavior, or even take complete control of the modem's operational capabilities. The vulnerability's exploitation potential is amplified by the fact that it can be triggered remotely through cellular network communications, meaning users could be compromised without their knowledge or consent. This type of vulnerability directly impacts the CIA triad of information security, compromising confidentiality through potential data interception, integrity through possible system modification, and availability through potential denial of service conditions. The vulnerability also creates opportunities for advanced persistent threats that could use the modem as a foothold for broader system compromise, as the modem typically operates with elevated privileges and access to core device functionalities.
Mitigation strategies for this vulnerability require a multi-layered approach focusing on both immediate patch deployment and network-level protections. Samsung addressed this issue through firmware updates and security patches released for affected devices, emphasizing the importance of keeping mobile device software current with security updates. Network operators should implement monitoring solutions to detect and block suspicious cellular traffic patterns that might indicate exploitation attempts. From a defensive perspective, the vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in embedded systems. Security professionals should consider implementing mobile device management solutions that can enforce security policies and ensure timely patch deployment across enterprise device fleets. Additionally, the vulnerability demonstrates the importance of supply chain security and the need for comprehensive security testing of embedded components, particularly those operating in trusted execution environments. Organizations should also consider network segmentation and traffic filtering to limit potential exploitation vectors, while maintaining awareness of the evolving threat landscape related to mobile device security vulnerabilities. The incident highlights the critical nature of modem security in mobile devices and the need for robust security architectures that can defend against attacks targeting these fundamental communication components.